Roof ventilator



FIG. 1 is a top plan view of a roof ventilator showing my new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a rear view thereof; and

FIG. 5 is a bottom view thereof. 

The ornamental design for a roof ventilator, as shown and described. 